It is widely known that one of the problem of bathrooms, both public and private, is to manage bad smells after the use of sanitary apparatus such as the toilet or the bidet. In particular, for those bathrooms that are provided with small-size openings, which may even be arranged in a high position and, therefore, are difficult to reach, the change of air becomes difficult, thus worsening the presence of a stagnant smell in the room itself.
Furthermore, there are bathrooms that have no windows or similar openings towards the outside (the so-called blind rooms), which typically require suction systems for stale air that operate by means of a fan.
These systems usually comprise a suction means, which typically is a tangential fan or a paddle wheel fan and is arranged on a structure that is at least partially recessed in the upper part of a wall or in the ceiling of the bathroom; the fan is activated by an electric motor, usually by means of a direct shaft transmission, so as to suck the air from the bathroom towards the outside.
The fan is connected to an air extraction duct, which is usually built-in in a wall of the building where the bathroom is located, so as to allow the air sucked to be carried towards a flue or towards the outside of the building.
These systems have the drawback to necessary require great masonry works during the creation of said air extraction ducts and are not efficient in terms of smell reduction in place.
In detail, indeed, these systems have the drawback to extract the air away with respect to the sanitary apparatus, namely far from the source of the smells itself and, especially in large and high rooms, once the smells have reached the system, they have already saturated most of the inner volume of the bathroom.
Furthermore, since the bathroom is a room that is not hermetically insulated from the others, part of the air sucked by the system is re-drawn, due to the modest pressure decrease in the room, for example by adjacent rooms and not directly by the sanitary apparatus. In order to improve the efficiency of these systems, one could use high-capacity or large-size fans, which, though, impose tight limits to the usability in terms of dimensions, noise produced (which is crucial, especially for buildings of civil use, during the night) and electrical input.
There are also direct smell sucking systems from the sanitary apparatus, such as the one described in patent no. GB 2 327 905 A, owned by Panfan International Limited, which discloses an apparatus for the removal of smells from rooms containing sanitary apparatus, which is provided with a fan that is connected to a water draining duct to drain water from the tank and is able to directly suck the smells from the sanitary apparatus, thus carrying the air sucked to the outside of the building.
Document GB 2 327 905 A, though, implies some drawbacks; firstly, as a matter of fact, the fan described in the document is inserted into the wall, which does not obviate the need for significant masonry works for the installation thereof and this is even more important if the apparatus has to be installed after the creation of the wall of the building. Secondly, furthermore, when the fan is disabled, there is a high risk that part of the smells flow again into the duct from the outside of the building (for example due to an air convection phenomenon—just think about the case in which the inner room is very hot and high and the outside of the building is cold: due to thermal convection, the air would tend to re-flow into the tube towards the sanitary apparatus). Finally, in order for the apparatus described in the document to effectively work, it is necessary for the apparatus itself to easily reach the outside of the building or an air outlet duct. Indeed, assuming to have blind rooms that do not communicate with any peripheral wall of the building, the path of the fan towards the outside would necessarily be long and winding. The loss of pressure inside the outlet duct would necessarily require the use of fan having a power that is much higher than the one that would be needed in case of a short duct, thus causing, in order to reach the same result, an increase in energy consumption and noise produced.
Finally, there are buildings with a particular historical or artistic value, in which, even if the bathroom communicates with a peripheral wall, nothing can be installed towards the outside of the building itself. Consequently, in this case, it would be necessary to have an outlet duct that is arranged on the outside or on the roof, with significant installation costs.
An effective solution for the drawbacks mentioned above is described in document EP 2 224 067 A1, owned by the Applicant.
More in detail, this document describes a device for eliminating smells for a flush type sanitary apparatus, wherein the sanitary apparatus is connected to a flush water supply device by means of a supply pipe. The device comprises a water and/or air inlet pipe, an outlet pipe and a suction box comprising a motorized ventilation means. The suction box is connected to the inlet pipe and to the outlet pipe, and the device has a siphon that is partially filled with water after the flushing of the sanitary apparatus. The siphon is connected to the ventilation means and the outlet pipe is connected to a sewerage system.
The device described in document EP 2 224 067 A1 allows users to easily eliminate smells by directly sucking the air inside the sanitary apparatus, thus avoiding or anyway minimizing their dispersion inside the bathroom.
Furthermore, for the entire duration of the use of the sanitary apparatus, possible bad smells are directly drawn and sucked from the place in which they are generated and follow a path that, starting from the sanitary apparatus, extends through the inlet pipe, the fan and the siphon in order to reach the outlet pipe. Hence, thanks to the presence of the siphon in the device, one can avoid the return of the bad smells already sucked or of bad smells coming from the sewerage system.